The Iceland international, who joined from Hoffenheim last month, cancelled out Marc-Antoine Fortune's opener and laid on the winner for Danny Graham. The visitors dominated for long spells as they followed up their 1-1 home draw against Chelsea with another impressive performance.

But Albion's woeful home record continued and they have collected just eight points at The Hawthorns compared to 18 on their travels. Roy Hodgson's side were often left chasing shadows with Sigurdsson and Joe Allen pulling the strings and Graham a constant threat.

And it was against the run of play that Fortune put West Brom ahead after 53 minutes. A Graham Dorrans corner was flicked on by Jonas Olsson and at the far post Fortune had time to steady himself before scoring.

Swansea needed only two minutes to draw level. Leon Britton released Neil Taylor and his low cross was side-footed past Ben Foster by Sigurdsson.

The game turned around on 59 minutes. This time Sigurdsson was the creator with a low ball to the near post and Graham made no mistake for his 10th goal of the season.